1. Field of the Invention
The present invention relates to a rotary switch.
2. Description of the Related Art
Conventionally, a rotary switch, which comprises a housing with a stationary contact and a rotor with a moving contact, is provided. The moving contact, which is connected and disconnected with the stationary contact, is rotatably supported on the housing in a direction of connecting and disconnecting the moving contact with the stationary contact (Japanese Laid-Open Patent Publication No. 2004-231094, for example).
For example, as shown in FIGS. 15 and 16, a rotary switch 100 having the above configuration is attached to a joint between a body 110 and a stand 120 in a motorcycle so as to detect the stand 120 stands. When the stand 120 stands during stop of the motorcycle, an engine of the motorcycle is disenabled to be started, so that it is possible too prevent the start of the motorcycle with the stand 120 standing.
As shown in FIG. 16, the stand 120 is pivotally attached to the body 110 with a bolt 130. A housing 101 of the rotary switch 100 includes a main body 102 which stores stationary contacts (not shown) and a part of a rotor 103, a cable draw-out portion 104 from which an electrical wire 140 electrically connected to the stationary contacts and a moving contact is pulled out, and a holding portion 105 which holds a protrusion 111 protruded from the body 110 with the cable draw-out portion 104. The housing 101 is connected with the body 110 by holding the protrusion 111 between the cable draw-out portion 104 and the holding portion 105. The rotor 103 is connected with the stand 120 by being screwed to the stand 120 with a screw 131 which is screwed in a screw hole 132 on the stand 110. When the stand 120 rotates with respect to the body 110 as shown by arrow A1 in FIG. 15, the rotor 103 works with the stand 120 and rotates with respect to the housing 101, and the state of the contact point (connection of the moving contact with the stationary contact) is switched based on whether the stand 120 stands or not. Moreover, a protrusion 121 which protrudes on the same direction as the protrusion 111 on the body 110 is provided on the stand 120. A connection spring 133 is provided between the protrusion 111 on the body 110 and the protrusion 121 on the stand 120. Since the connecting spring 133 is made of an extension spring, the stand 120 maintains its state whether to stand during stop of the motorcycle or be stored during running with a tensile force of the connecting spring 133.
A screw insertion hole 103a through which the screw 131 penetrates for fixing the rotor 100 to the stand 120 receives a force at every time when the stand 120 changes its state, so that a metal component 103b of cylindrical shape is provided to configure an inner surface of the screw insertion hole 103a with an insert molding of the rotor 103 to reinforce the screw insertion hole 103a. However, when the metal component 103b is used in the rotor 103, a production cost relatively increases.
FIG. 17 shows a configuration of the stationary contacts in the main body 102 of the housing 101 of the conventional rotary switch 100. A annular recess 102a having a circular cross section perpendicular to a depth direction thereof is provided on the main body 102 of the housing 101. A plurality of (for example two) stationary contacts 106A and 106B each having a circular arc shape is arranged along a periphery of the annular recess 102a. When the rotor 103 rotates on a center axis of the annular recess 102a with respect to the main body 102, the moving contact (not shown) moves following to the rotation of the rotor 103 between a position to contact the stationary contact 106A which corresponding to the position when the stand 120 stands, for example, and another position to contact the stationary contact 106B which corresponds to the position when the stand 120 turns up.
Since the stationary contacts 106A and 106B are arranged along the periphery of the annular recess 102a, the stationary contacts 106A and 106B can be strongly held on the main body 102 of the housing 101 by embedding a part of each of the stationary contacts 106A and 106B in the periphery of the annular recess 102a. In addition, the stationary contacts 106A and 106B can be positioned by the inner surface of the annular recess 102a in manufacturing of the rotary switch 100.
When a distance D1 between the stationary contacts 106A and 106B is enlarged in order to secure electrical insulation between the stationary contacts 106A and 106B, the moving contact falls into a gap between the stationary contacts 106A and 106B in switching the contact, and thereby a malfunction occurs.
In the example shown in FIG. 17, a groove 102c is provided between the stationary contacts 106A and 106B on a bottom surface 102b of the annular recess 102a to secure a creeping distance D2 between the stationary contacts 106A and 106B along the bottom surface 102b of the annular recess 102a without enlarging the distance D1 between the stationary contacts 106A and 106B. According to such a conventional configuration, it, however, is impossible to secure the creeping distance D3 along the periphery of the annular recess 102a. 